Time to drag my winter bike out for a bit of a fettling unfortunately the seat pin is solid in the frame (One One 456) I know, I know I should have stripped and greased it BEFORE putting it away in the spring. Any tips for freeing up alloy seat post stuck in a steel frame? Tried WD40 and hitting it with a hammer and a piece of wood but she ain’t budgin”

Probably chemically fused now. Check out caustic soda use for a seat post.

Worth a go with Plus Gas. Take BB out and pour it down seat tube/get creative.

https://www.google.co.uk/search?q=plus+gas&rlz=1C1CHMO_en-GBGB554GB554&oq=plus+gas&aqs=chrome..69i57j0l5.3087j0j7&sourceid=chrome&es_sm=122&ie=UTF-8#q=plus+gas&safe=off&tbm=shop

Plus Gas? I will give that a go, had not thought about taking out BB, good idea, thanks!

Or have it melted out as part of a respray….

Plus gas, hold seatpost tightly in a vice, turn frame

Coke works too, pour it into the frame from the BB, leave overnight…post in a vice then use the frame as a lever and turn…

http://sheldonbrown.com/stuck-seatposts.html

Genuine full fat Coke a Cola. Honestly.

Accept the post is a write off and put it in a vice and twist the frame around it following liberal application of oil and if you’re a believer prior to that, the coke or caustic soda tricks. Should easily do the trick.

Did this on a Ti frame/ali post combo a few weeks ago for my next door neighbour and all was fine.

Strip frame, place frame bb up with seatpost clamp in secure vise, pour/spray plus gas down bb or bottle tube bosses every few hours when possible, leave 24hrs and grab frame at head tube/seat stays and crack off the seat tube bond.

OK good advice guys, I still can’t budge it so off to a mates who has a vice and try the twisting thing. Coca Cola? Really? May as well give it a go as well…

Getting liquid to penetrate from the top isn’t easy (even if the seatpost wasn’t sealed in, it’d still rather roll off the side thna down any gap). But turning the bike upside down and pouring in from the BB gives it nowhere to go but past the seatpost (well, unless there are other holes). Remember it’ll make a bloody mess though.